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Galactic time-keeping

  1. Nov 4, 2014 #1
    Here are two related problems I was thinking about and wonder if you can chime in (didn't see any related threads on these issues already):

    1. Say there is a galactic "community" made-up of various species of sentient beings (humans being one of them). Say they have a central meeting place where political affairs are discussed, treaties are signed, etc. The question is this: Would such an arrangement require a sort of universal time-keeping standard? I.e. how would the humans arrange a meeting with aliens on the other side of the galaxy?

    Of course they wouldn't say, "Ok, let's meet at point X on Wednesday at 5:00pm" since outside of Earth the 24 hour clock and Gregorian calendar are completely meaningless, and probably other reasons you guys know about that I do not. This is a big problem I have run into and I don't even know if I'm thinking of it in the right terms.

    I would think that a galactic community that has to arrange meetings and schedule things would have some sort of universal, objective standard of time and date that could be easily referenced. Any one have any ideas or thoughts on this?

    2. Say there are a number of human colonies located on various exoplanets separated by tens of thousands of light years. Forgetting how they actually got there in the first place, let's say they have some sort of central government (in addition to their planetary, national, local governments, etc.)

    What ways might a civilization like this maintain an objective calendar-keeping system? I assume that if whatever the capital world of such a civilization would create a new calendar based on the orbital period of their own star, but would do you think this would be absolutely necessary?
     
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  3. Nov 5, 2014 #2

    phinds

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    None of your questions make any sense without the existence of faster than light communications and/or travel and since those don't exist and are believed to be impossible, I don't see how there can be any meaningful answers to your questions.
     
  4. Nov 5, 2014 #3
    Some multiple of plank seconds I would think.
     
  5. Nov 5, 2014 #4

    phinds

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    Yes, that would make sense to record the PASSAGE of time but has nothing to do with the OP's question of how do you establish a synchronized galactic standard for what TIME it is.
     
  6. Nov 5, 2014 #5

    HallsofIvy

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    Are those measured or written on a flat board? I would think Planck seconds would be better.
     
  7. Nov 5, 2014 #6

    Vanadium 50

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    I don't see the problem. You send a message to the Little Green Men that says "These are seconds. One. Two. Three. In 864,000 of them, please meet us on Remulak".
     
  8. Nov 5, 2014 #7

    Bandersnatch

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    Yeah, I'm with Vanadium on this. Much easier for each planet to stick to local days and years, or what makes sense to them. It seems more sensible to use simple conversion algorithm to translate dates other planets are using than enforce arbitrary unified time scheme.
    It's not that much different from the issue of metric and imperial systems we have to deal with, only on a much larger scale.
     
  9. Nov 5, 2014 #8

    Matterwave

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    Consider that the galaxy is 100,000 light years across. Say I want to schedule a meeting. In order for me to notify the whole galaxy AND give them reasonable time to come to the meeting place, I better set that meeting ~200,000 years in the future. And this is assuming that the inhabitants of the galaxy can travel very close to the speed of light. :D

    In addition, participants from the other side of the galaxy can expect a 200,000 year round trip journey to attend my meeting...so this better be a pretty darn important meeting!
     
  10. Nov 5, 2014 #9

    Jonathan Scott

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    So far the answers seem to be only considering the scale of "galactic time" and not how it would be synchronised. For accurate timing, there would have to be some agreement on a rest frame.

    On the other aspect of faster-than-light communication, it is known scientifically that if faster than light travel is possible relative to an arbitrary inertial frame of reference, then this leads to causality violation, and it seems reasonable to assume that this means it is impossible. However, there is no similar scientific disproof of the possibility of communication or travel at unlimited speed relative to some universally synchronised preferred frame, which is usually called "subspace" in science fiction. At present, there is no experimental evidence for such a preferred frame, so we assume it does not exist, and we do not know of anything which currently violates the principle of relativity in this way. However, it is sometimes used for example as part of a model for explaining quantum entanglement, and I think that for purposes of science fiction on a galactic scale the "subspace" idea seems quite acceptable.
     
  11. Nov 5, 2014 #10
    even with the ability to travel from one point to another with a reasonable delay (not in 100's or 10's of thousands of years) each group would need a form of communication learned by all. including math which would allow for a standard of time passage each could agree on.
     
  12. Nov 5, 2014 #11

    jim mcnamara

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    I always liked Alfred Bester's solution in 'The stars my destination' - jaunting - an innate human ability to teleport oneself instantly, even across the voids of space. Solves lots of problems like the ones mentioned above. Heck I reread it 30 years ago, so I guess I'm due for a reread now.
     
  13. Nov 5, 2014 #12

    russ_watters

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    No there doesn't. This isn't any more complicated than arranging meetings in different time zones: Let's meet at 2:00 pm EST (Eastern Standard Time). By stating the time zone I'm meausuring the time in I've specified myself to be the rest/preferred frame. If I want to be nice for a client in California, I might specify that we have the meeting at 11:00 am PST, doing the conversion for him and specifying him to be the rest/preferred frame.

    Now, interstellar meetings would be problematic without FTL communications, but that's a problem that exists independent of the preferred frame issue. I can specify that the meeting be in person or if it requires only a one way communication (tell me if you like cheese), I can specify when, in my frame, I want the answer and you'll have to calculate when to send it.
     
  14. Nov 6, 2014 #13

    Danger

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    This subject is the very reason that Gene Roddenberry "invented" the Stardate system used in the Star Trek franchise; it was meant to be not only a universal reference, but also one that took into account relativistic time dilation during space flight. (Of course, he never explained how it worked... :rolleyes:)
     
  15. Nov 6, 2014 #14
    You know I think there is a kind of expectation of thinking of a great idea to solve the problem.

    If there is a place of some special significance - then we just count the passage of time in that one place.

    For practical purposes - how many different time standards there would be. 1000? OK. How big would be a standard record about each time measurement method? 1KB?
    So I can either hope for:
    1) effective intergalactic cooperation and lack of chauvinism;
    2) a simple converter application in my mobile phone that would need one megabyte of free place.
     
  16. Nov 6, 2014 #15
    Why not use the rotation of the galaxy as a frame of reference? The galaxy has a defined rotational speed, creating a time system based on revolutions our own galaxy since an agreed upon beginning of time (The Big Bang) would seem feasible. I mean, you'd be measuring the rotation based on a mathematical equivalency to each Race's preferred unit of measurement, but a standard of time could technically be agreed upon, based on the rotational speed of the galaxy and how many times it completes a full cycle.
     
  17. Nov 6, 2014 #16

    Danger

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    That seems a bit optimistic, since we have a couple of dozen on Earth alone.
     
  18. Nov 6, 2014 #17
    guess the fairly stable cycles of a pulsar could be used as a interstellar clock as long as each participant can actually see the same pulsar.
     
  19. Nov 8, 2014 #18

    Danger

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    That might be about the closest thing available. It still wouldn't be absolute, though, because a pulsar's period varies over time and it will appear to spin faster the farther one is from it due to "speed of light" observational lag.

    edit: On the other hand... hmmm.... I suppose that such could be compensated for simply by maintaining knowledge of how far one is from it when the observation is made.
     
  20. Nov 8, 2014 #19

    mfb

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    Instead of a pulsar, you can also use an atomic clock and transmit the time signal to the whole galaxy. Sure, you have to take signal delays into account.
    This is not a new concept, we use the same approach in the solar system already (with signal delays of several hours for the Voyager probes and New Horizons).

    You can then convert this universal time to local time standards.
     
  21. Nov 8, 2014 #20

    Danger

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    Of course, if other civilizations are anything like ours, it will never happen. It would take until the end of the Universe for the various cultures to decide upon which pulsar or atomic clock to use. :rolleyes:
     
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